Income Taxes - Provisions/ Benefit (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Federal	$ 0	$ 0	$ 0
State	21	26	191
Foreign	472	595	1,407
Total current	493	621	1,598
Federal	0	0	0
State	0	0	0
Foreign	(237)	12	(61)
Total deferred	(237)	12	(61)
Provision for income taxes	$ 256	$ 633	$ 1,537